Working vehicle with transverse travel system

ABSTRACT

Front wheels ( 3 ) are attached to transmission devices ( 30 ) which are mounted to the vehicle body ( 2 ) to be rotatable around vertical axes ( 27 ), and rotating means ( 55 ) are provided between the side of the vehicle body ( 2 ) and the transmission devices ( 30 ), whereby the front wheels are steered to turn laterally at substantially right angles. An electric motor ( 40 ) is attached to the transmission device ( 30 ) to be located under the vertical axis ( 27 ). A case body ( 41 ) of the electric motor ( 40 ) is constructed by an outer case part ( 41 A) and a non-loaded side bracket ( 41 B), and a loaded side end portion of the outer case-part ( 41 A) is connected to the transmission device case body ( 31 ). The drive shaft ( 44 ) is rotatably supported by the non-loaded side bracket ( 41 B) at one end and by the transmission device case body ( 31 ) at the other end. A driving portion ( 34 ) provided at the other end side of the drive shaft ( 44 ) is operatively connected to an axle ( 28 ). As a result, a traveling drive device section can be constructed to be compact with assembling easiness.

TECHNICAL FIELD

[0001] The present invention relates to a working vehicle with alaterally traveling system which can switch the working vehicle tolateral traveling.

BACKGROUND ART

[0002] Conventionally, a self-propelled working truck which is found inJapanese Patent Unexamined Publication No. 2-306879 is proposed as aworking vehicle that can be switched to lateral traveling.

[0003] In this conventional construction, on a bottom face of a frame,two drive wheels located on one diagonal line are provided via adirection turning shaft to be turnable, while two free idler wheelslocated on the other diagonal line are provided to be turnable, and boththe drive wheels are operatively connected to each other by a directionchanging connecting part. The connecting part is constructed by turninglevers provided at a side of the direction turning shaft, a pair of rodsconnected to these turning levers at tip ends thereof, a hydrauliccylinder provided along the diagonal line on which both the drive wheelare located, and a connecting fitting which is provided at an extendablerod of this hydraulic cylinder and which connects inner ends of the pairof rods.

[0004] The driving wheels are attached to support fittings via a driveshaft, and the support fitting is provided at the frame side via thedirection turning shaft to be turnable. Further, a drive motor isprovided at the support fitting, and a worm gear projected downward fromthe drive motor is meshed with a worm wheel of the drive shaft.

[0005] According to the conventional construction as described above, byextending and contracting the hydraulic cylinder, the rods are pushedand drawn along the diagonal line via the connecting fitting, wherebyboth the drive wheels can be turned in the opposite direction from eachother via the turning levers and the direction turning shaft. Therotation of the drive motor is transmitted to the worm gear, worm wheel,and the drive shaft, whereby the drive wheels can be rotationallydriven.

[0006] However in the above-described conventional construction, thedrive motor (traveling drive device) is provided to the support fittingoutside the turning axis, whereby the width of the drive wheel partwhich is turned becomes large, and therefore a large turning space hasto be secured, thus making the width (length) of the vehicle body largerand increasing the size of the entire body. The drive motor and the likeare independently constructed and thereafter installed, and thus thesize of the entire body is increased.

DISCLOSURE OF INVENTION

[0007] The present invention has its object to provide a working vehiclewith a laterally traveling system which is of a type capable of steeringdrive type front wheels to turn at substantially right angles in alateral direction while a traveling drive device section is constructedto be compact with excellent assembling easiness.

[0008] In order to attain the above object, a working vehicle with alaterally traveling system of the present invention comprises a pair ofleft and right front wheels and a pair of left and right rear wheelsmounted to a vehicle body to be turnable by 90 degrees, the pair of leftand right front wheels being attached to transmission devices mounted tothe vehicle body to be rotatable around vertical axes, rotating meansprovided between the vehicle body and the transmission devices, and atravel-driving electric motor located under the vertical axis andattached to each of the transmission devices, and is characterized inthat each travel-driving electric motor has a case body comprising andouter case part and a non-loaded side bracket, the outer case parthaving a loaded side end portion connected to a case body of thetransmission device, one end of a drive shaft mounted with a rotor isrotatably supported by the non-loaded side bracket, and the other end isrotatably supported by the case body of the transmission device, and theother end of the drive shaft is provided with a driving portion of thetransmission device, which driving portion is operatively connected toan axle.

[0009] According to the invention with the above-described construction,the loaded side end portion of the outer case part in the case body ofthe electric motor is connected to the case body of the transmissiondevice, and the other end of the drive shaft is rotatably supported atthe case body of the transmission device, whereby the number of thecomponents of the electric motor is reduced to be able to simplify theconstruction, and the section of the electric motor is improved inassembling easiness (mounting easiness), and can be constructed to becompact. In addition, the electric motor is located under the verticalaxis, whereby the width of the turning front wheel part, namely, thespace for turning can be made smaller, thus making it possible to reducethe width (length) of the vehicle body and downsize the entire body.

[0010] During normal traveling, the left and right front wheels and theleft and right rear wheels faces the longitudinal direction. Whenswitching from the normal traveling to the laterally traveling, therotating means are operated first to rotate the transmission devicesaround the vertical axes, whereby the front wheels can be turned by 90degrees (turned laterally at substantially right angles) with respect tothe vehicle body. Here, the electric motors and the front wheels arelocated under the vertical axes, whereby turning of the electric motors,the front wheels and the like by 90 degrees is performed easily,smoothly and compactly. After the drive type front wheels are turnedlaterally at substantially right angles (steered), the front wheels aredriven in the normal and reverse direction by the electric motors,whereby the working vehicle can laterally travel either to the left orright.

[0011] The preferred embodiment in the working vehicle with thelaterally traveling system of the present invention is characterized inthat the mast is disposed at the front end side of the vehicle body, andforks are attached to the mast.

[0012] According to this embodiment, during normal traveling, the leftand right front wheels and the left and right rear wheels face thelongitudinal direction, and by manipulating the lever for the lift, thefork is hoisted and lowered along the mast to perform a fork operationfor a predetermined period of time. While it is of the type whichenables a normal fork operation like this, it steers the drive typefront wheels to face laterally at substantially right angles to make itpossible to perform lateral traveling, and for example, an elongateobject can be transported easily via the forks.

BRIEF DESCRIPTION OF DRAWINGS

[0013]FIG. 1 shows an embodiment of the present invention, and is apartially cutaway front view of a front wheel part of a working vehiclewith a laterally traveling system;

[0014]FIG. 2 is a side view of the working vehicle with the samelaterally traveling system during normal traveling;

[0015]FIG. 3 is a side view of the front wheel part of the workingvehicle with the same laterally traveling system;

[0016]FIG. 4 is a schematic plan view of the working vehicle with thesame laterally traveling system during normal traveling; and

[0017]FIG. 5 is a schematic plan view of the working vehicle with thesame laterally traveling system during lateral traveling.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] An embodiment of the present invention will be explained belowbased on the drawings. In FIG. 2, a fork lift 1 as an example of aworking vehicle is provided with a pair of left and right front wheels(drive wheels) 3 to a front portion of a vehicle body 2, a pair of leftand right rear wheels (idler wheels) 4 to a rear portion thereof, and adriver's seat 5 above the front portion of the vehicle body 2. Avertically extendable mast 6 is disposed at the front end section of theaforementioned vehicle body 2 to be rotatable in a longitudinaldirection via a connecting shaft 7 in a vehicle width direction, a tiltcylinder 8 which effects the longitudinal rotation is provided betweenthe vehicle body 2 and the mast 6.

[0019] The mast 6 is constructed by a pair of left and right outerframes 9 at a side of the fork lift 1, and a pair of left and rightinner frames 10 descendable and ascendable by being guided by the outerframes 9, and a lift cylinder 11 is provided between the outer frame 9and the inner frame 10. A lift bracket 12 is provided to be capable ofvertically moving by being guided on the inner frame 10, and a pair ofleft and right forks 13 are attached to the lift bracket 12 via a pairof vertical finger bars.

[0020] The driver's seat 5 is provided with a seat 15, a steering wheel16 located in front of the seat 15 and the like, and a head guard 19 isprovided thereabove via a front pipe 17 and a rear pipe 18 which areerected from the vehicle body 2. Further, a counterweight 20 is providedat a back of the seat 15 on the vehicle body 2.

[0021] In FIG. 1 to FIG. 4, the pair of left and right front wheels 3and the pair of the left and right rear wheels 4 are mounted to thevehicle body 2 so that they can be turned by 90 degrees (laterallyturnable at substantially right angles) Namely, on both sides of thefront portion of the vehicle body 2, vertical shafts 26 are provided tobe rotatable around vertical axes 27 via the respective bearings 25. Atransmission device case body 31 of a transmission device 30 is fixed ata lower end of the vertical axis 26, whereby the transmission device 30is mounted to the vehicle body 2 to be rotatable around the verticalaxis 27.

[0022] Here, the transmission device case body 31 is constructed by aninner case part 31A in an inverted L-shape, and an outer case part 31Battached to an outer face side of a vertical plate portion in this innercase part 31A, and a lateral plate portion of the inner case part 31A isfixed at a lower end of the vertical axis 26.

[0023] In the upper part of the transmission device case body 31, an oilseal 32 can be placed in a penetrated portion formed in the inner casepart 31A, and a bearing 33 can be placed in a recessed portion formed inthe outer case part 31B. A cylindrical driving gear (driving portion) 34is rotatably supported by this bearing 33 via a cylindrical boss portion34 a.

[0024] Further, an axle 28 is rotatably provided via a wheel bearing 35at the inner case part 31A in the lower part of the transmission devicecase body 31, a driven gear (driven part) 36 is attached to the axle 28to be located inside the transmission device case body 31, a rim 3A ofthe front wheel 3 is detachably attached to a part projected to theoutside of the transmission device case body 31 via a rotational flange29 and the like. The driving gear 34 and the driven gear 36 areoperatively connected via a reduction gear mechanism 37 located insidethe transmission device case body 31. An example of the transmissiondevice 30 is constructed by the above-described components 31 to 37.

[0025] An electric motor 40 for traveling drive that is located belowthe vertical axis 27 is attached to the transmission device 30. Namely,a case body 41 of the electric motor 40 is constructed by a cylindricalouter case part 41A, and a non-loaded side bracket 41B which blocks anon-loaded side end portion (non-loaded side end) of the outer case part41A, and a loaded side end portion of the outer case part 41A isintegrated with a inner face side of the vertical plate portion of theinner case part 31A in the transmission device case body 31 by weldingor the like. As a result, the inner case part 31A of the transmissiondevice case body 31 is also used as a loaded side end bracket in theelectric motor 40.

[0026] A stator component such as a stator 42 is provided on an innercircumferential face of the outer case part 41A. The drive shaft 44mounted with a rotor 43 is placed inside the case body 41, and one endof the drive shaft 44 is rotatably supported at a bearing 45 in arecessed portion formed in the non-loaded side bracket 41B. The otherend of the drive shaft 44 is inserted through the driving gear 34 andconnected therewith.

[0027] As a result, the other end of the drive shaft 44 is rotatablysupported at the outer case part 31B of the transmission device casebody 31 via the cylindrical boss part 34 a of the driving gear 34 andthe bearing 33. The driving gear 34 provided at the other end of thedrive shaft 44 is operatively connected to the axle 28 via the reductiongear mechanism 37 and the driven gear 36, whereby the pair of left andright front wheels 3 are operatively connected to the respective driveshafts 44 of the electric motors 40. On this occasion, the front wheel 3is constructed to be located at an area immediately below the verticalaxis 27. An example of the electric motor 40 is constructed by theabove-described components 41 to 45 and the like.

[0028] A battery 50 is mounted on the vehicle body 2, and a controller51 is attached to the battery 50. A cable 52 from the controller 51 isconnected to each of the electric motors 40.

[0029] Front wheel rotating means 55 for rotating the left and righttransmission devices 30 are provided. Namely, a turning cylinder 57 isprovided to be relatively rotatable between a link 56 provided at anupper end portion of the vertical shafts 26 and the vehicle body 2,whereby the left and right front wheels 3 are constructed to turn inopposite directions from each other to face laterally at substantiallyright angles, by extension movement of the turning cylinder 57. Anexample of the front wheel rotating means 55 is constructed by theabove-described components 56, 57 and the like.

[0030] In each of the pair of left and right rear wheels 4, a rim 4A isattached to a vertical plate portion in a turning member 60 via an axleand the like to be freely rotatable, and a lateral plate portion in theturning member 60 is attached to the vehicle body 2 to be rotatablearound a vertical axis 63 via a wheel bearing 61 and a vertical shaft62. In this situation, the rear wheel 4 is constructed to be located atan area immediately below the vertical axis 63.

[0031] Rear wheel rotating means 65 for rotating the left and rightturning members 60 is provided. Namely, free ends of links 66 providedat upper end portions of the vertical shafts 62 are connected by acommon link 67 in a vehicle width direction, and a turning cylinder 68is provided between a middle portion of the common link 67 and thevehicle body 2 to be relatively rotatable. Accordingly, the left andright front wheels 3 are constructed to be turned in the same directionto face laterally at substantially right angles by extension movement ofthe turning cylinder 68. An example of the rear wheel rotating means 65is constructed by the above-described components 66 to 68 and the like.

[0032] An operation in the above-described embodiment will be explainedbelow.

[0033] In the electric motor 40 section, a loaded side end portion ofthe outer case part 41A in the case body 41 is directly connected to theinner case part 31A of the transmission device case body 31, and theother end of the drive shaft 44 is rotatably supported by the outer casepart 31B of the transmission device case body 31, whereby the electricmotor 40 section can be constructed to be compact with excellentassembling easiness. In addition, the electric motor 40 is located underthe vertical axis 27, whereby the width of the front wheel part which isturned, namely, the space for turning can be made smaller, and the widthof the vehicle body 2 (length) is decreased, thus making it possible toreduce the entire body in size.

[0034] The solid lines in FIG. 1 and FIG. 2, and FIG. 4 show situationsat the time of normal traveling. In these situations, the left and rightfront wheels 3 and the left and right rear wheels 4 face thelongitudinal direction. The fork lift 1 like this can travel byoperation of the steering wheel 16 by the operator seated in the seat 15of the driver's seat 5. Namely, electric power of the battery 50 iscontrolled by the controller 51, and thereafter it is supplied to theelectric motors 40 via the cable 52, whereby the front wheels 3 aredriven in a normal and reverse direction and the fork lift 1 can travelin a longitudinal direction.

[0035] The lift cylinder 11 is operated by manipulating the lift lever,whereby the fork 13 can be hoisted and lowered along the mast 6 via thelift bracket 12 and the like, thus making it possible to perform a forkoperation for a predetermined period of time. The tilt cylinder 8 isoperated by manipulating the tilt lever, whereby the mast 6 can berotated (tilted) around the connecting shaft 7, thus making it possibleto change the posture of the fork 13 via the lift bracket 12 and thelike.

[0036] When switching from the normal traveling as described above tolateral traveling, the front wheel rotating means 55 and the rear wheelrotating means 65 are operated by manipulating a lever type lateral modeswitch (not shown) at first to tilt the lever.

[0037] Namely, both the turning cylinders 57 of the front wheel rotatingmeans 55 are synchronized and extended, and the transmission devices 30are rotated in a reverse direction around the vertical axes 27 via thelinks 56, whereby the front wheels 3 are turned by 90 degrees withrespect to the vehicle body 2 (laterally turned at substantially rightangles) as shown by the phantom lines in FIG. 1 and FIG. 2, and FIG. 5.

[0038] Since the electric motors 40 and the front wheels 3 are locatedunder the vertical axes 27 in this situation, the electric motors 40,the front wheels 3 and the like can be turned to 90 degrees easily,smoothly, and compactly.

[0039] Further, the turning cylinder 68 of the rear wheel rotating means65 is extensively moved, and the turning members 60 are rotated in thesame direction around the vertical axes 63 via the common link 67 andthe links 66, whereby the rear wheels 4 are turned by 90 degrees(laterally turned at substantially right angles) with respect to thevehicle body 2 as shown by the phantom lines in FIG. 1 and FIG. 2, andFIG. 5. Since the rear wheels 4 are located under the vertical axes 63,the rear wheels 4 and the like are made compact and can be turned by 90degrees.

[0040] The turning of the front wheels 3 and the rear wheels 4 asdescribed above, namely, turning the front wheels 3 and the rear wheels4 laterally at substantially right angles is sensed by the sensor, andan indicator lamp is lit, whereby a laterally traveling mode is madepossible. Accordingly, electric power of the battery 50 is controlled bythe controller 51 and thereafter it is supplied to both the electricmotors 40 via the cable 52, whereby the front wheels 3 are driven in thenormal and reverse direction, thus making it possible to make the forklift 1 travel laterally on the left and right. In this situation, thepair of left and right rear wheels 4 perform slave rotation.

[0041] As a result that lateral traveling can be performed as describedabove, for example, an elongate object can be transported easily via thefork 13. Compensation of straightness in lateral traveling isfacilitated by tilting the lever longitudinally to operate the turningcylinder 57 slightly to perform fine tuning of the angles of the frontwheels 3, or by operating the turning cylinder 68 slightly to performfine tuning of the angles of the rear wheels 4.

[0042] In the above-described embodiment, a counter type fork lift 1 isshown as a working vehicle, but the same operation can be obtained if alarge-scale transporter, a loader, a side fork lift and the like areused as the working vehicle.

[0043] In the above-described embodiment, the cylindrical driving gear34 is adopted as the drive part to make a type in which the drive shaft44 is linked with the driving gear 34, but this may be a drive part of atype in which a driving gear is directly formed at the other end of thedrive shaft 44. In this case, the number of the components of thetransmission device 30 can be reduced and the construction can befurther simplified.

[0044] In the above-described embodiment, a type in which the pair ofleft and right rear wheels 4 are forcibly turned by the rear wheelrotating means 65 is adopted, but a turning caster type which is turnedby following may be adopted. Out of the pair of left and right rearwheels 4, one of the rear wheels 4 may be a steering type by a handlewheel, and the other one of the rear wheels 4 may be a turning castertype, and in this case, when switching to lateral traveling, the one ofthe rear wheels 4 is forcibly turned by the cylinder and the like.

[0045] In the above-described embodiment, a type in which the pair ofleft and right front wheels 3 are independently rotated by therespective front wheel rotating means 55 is shown, but this may be atype in which common front wheel rotating means for simultaneouslyrotating the pair of left and right front wheels 3 is provided.

1. A working vehicle with a laterally traveling system, comprising: apair of left and right front wheels and a pair of left and right rearwheels mounted to a vehicle body to be turnable by 90 degrees, the pairof left and right front wheels being attached to transmission devicesmounted to the vehicle body to be rotatable around vertical axes; androtating means provided between the vehicle body and the transmissiondevices, a travel-driving electric motor located under the vertical axisand attached to each of the transmission devices, characterized in that:each travel-driving electric motor has a case body comprising an outercase part and a non-loaded side bracket, the outer case part having aloaded side end portion connected to a case body of the transmissiondevice; one end of a drive shaft mounted with a rotor is rotatablysupported by the non-loaded side bracket and the other end of the driveshaft is rotatably supported by the case body of the transmissiondevice; and the other end of the drive shaft is provided with a drivingportion of the transmission device, and this driving portion isoperatively connected to an axle.
 2. The working vehicle with thelaterally traveling system according to claim 1, characterized in that amast is disposed at a front end side of the vehicle body and forks areattached to the mast.